Question

I’m trying to iterate over an NSMutableDictionary and I cannot seem to get what I want. I have a dictionary mapping strings to colors like so…

squareColors = [NSMutableDictionary dictionaryWithObjects: [NSMutableArray arrayWithObjects:
                                                                [NSNumber numberWithInt:0],
                                                                [NSNumber numberWithInt:0],
                                                                [NSNumber numberWithInt:0],
                                                                [NSNumber numberWithInt:0],
                                                                [NSNumber numberWithInt:0],
                                                                nil]

                                                      forKeys: [NSMutableArray arrayWithObjects:
                                                                @"yellow",
                                                                @"blue",
                                                                @"green",
                                                                @"purple",
                                                                @"orange",
                                                                nil]];

Over time the value of each entry will increase. Every once in a while I want to look into the dictionary and select the color with the highest count. How might I do that? Here’s what I’m trying, but I’m unfamiliar with blocks.

__block int mostSquares = 0;
__block NSString* color = @"";
/* Look through the dictionary to find the color with the most number of squares */
[squareColors enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
   NSLog(@"%@ => %@", key, obj);
   NSInteger count = [key integerValue];
   if (count > mostSquares)
   {
        color = key;
        mostSquares = count;
   }
}];

Answer 1

You have a very simple bug in your code. This line:

NSInteger count = [key integerValue];

should be:

NSInteger count = [obj integerValue];

‘key’ is the color name, obj is the number. As you have it, count gets set to 0 for each iteration because calling integerValue on a non-numeric string gives you 0.